return source;
    }

    @Override
    public Optional<Map<String, String>> userProperties() {
        if (commandLine.hasOption(CLIManager.USER_PROPERTY)) {
            return Optional.of(toMap(commandLine.getOptionProperties(CLIManager.USER_PROPERTY)));
        }
        return Optional.empty();
    }

    @Override
    public Optional<Boolean> showVersionAndExit() {

        // are most dominant.
        // ----------------------------------------------------------------------

        Properties userSpecifiedProperties =
                commandLine.getOptionProperties(String.valueOf(CLIManager.SET_USER_PROPERTY));
        userProperties.putAll(userSpecifiedProperties);

        // ----------------------------------------------------------------------
        // Load config files